Most of the speakers presently available include a speaker frame having a plurality of bolt holes formed in the circumference thereof. The speaker frame is fixed with bolts to a baffle plate or a member constituting a door of a vehicle, and a grille is attached to the speaker frame.
For example, referring to FIG. 3, a grille 3 having a decorative net 3A stretched thereover is fitted to a rim portion 2A formed on the circumferential edge portion of a speaker frame 2 of a speaker unit 1.
Referring to FIG. 4, when a grille 3 is attached to a speaker frame 2, the grille 3 is fastened to the speaker frame 2 when a speaker is attached to a car-body member. Further, as shown in FIG. 5, there is a case where a grille 3 having no decorative net is fastened to speaker frame 2 so as to be attached thereto, and then a decorative net 3A is bonded to the grille 3.
In the above-mentioned speakers shown in FIGS. 3-5, when attaching a speaker, it is necessary to attach a grille or a decorative net to the grille, and in some cases, speaker head portions of bolts used for attaching the speaker are exposed on the surface. In a speaker in which bolt head portions are not exposed, there are problems in that it is necessary to provide a rim at the circumference of a speaker frame so that the grille can be fitted to the rim. Further, the speaker frame is complicated in shape, and the fitted frame often pops out by vibrations or the like of the vehicle.